At a glance
| Timeline | 4 months |
|---|---|
| Team | 3 developers |
| Stack | React Native · Node.js · Express · MongoDB · JWT · Firebase Cloud Messaging |
The problem
Splitting shared costs across a group is deceptively hard. Balances have to stay correct while several people add expenses at once, and everyone needs to see the same number at the same time. Doing that on top of a plain CRUD API produces stale balances and arguments about who owes what.
The approach
Balances are derived from the transaction log rather than stored as a mutable field, so they can never drift out of sync with the expenses behind them. Settlement is modelled as its own transaction type, which keeps history auditable. JWT auth with refresh tokens covers the mobile session, and Firebase handles push so users hear about a new expense without opening the app.
Stack
Work like this is quoted under web development services, with fixed prices agreed before anything starts.
Related: what a custom web application costs · how to choose a web development company
Built by Muhammad Mubashar Shahzad — React & MERN developer, WebDevStudio.